Telephone receiver



Much 29 1927' w. E. LA PEARLE 'ET Ax. 1622950 TELEPHONE RECEIVER Filed Dec. 10, 1925 .Za Pear/t.

Patented Mar. 29, 1927.

UNITED STATES PATENT OFFICE.

WILLIAM E. `LA. PEABLE ANDWE:LIAII E. LA PEABLE, 0F SALT LAKE CITY, UTA..

TELEPHONE um Application flied December 10. IBIS. Serial No. 74,884.

This invention relates to sound reproducing devices of the telephone receiver type.

Primarily. the devlee is intended for use as part of a radio loud s eaker. although it mayV well he. used for otier sound rcpri'iducing purposes.

By means of the invention, it is sought not only to provide for greater rolame and increased sensitiveness in a. dcvicoof this' character, but also to etlcct a saving in cost and time of production and repair.

More specifically. it is intended to pro- Y vide an improved mounting for the armatare associated with tho usual electro-magnnct of thc device, which will result in in| proved reproduction. The provision of facilities for ready adjustment of parts for tuning and other purposes are also objects of the invention.

lVith regard to repairs and replacements, particularly those involving the armature, s .cial provisions are made so as to render tiese extremely simple and inexpensive. Heretofore, the armature has been `so-mounted that, in order to remove it for repair or other purposes. it ,has been necessary to first remove the electro-magnet and` in some case", to entirely disassemblo the electromagnet. Some manufacturers, rather than take the time to do this, discard the entire clectm-mag'net. together with the armature, and replace these with. new parts. The present. invention provides' a receiver in which the armature may be removed and replaced readily without disturbing the elcctrofmagnet. Provision isalso made to assure accurate reassembly of the parts with reference to each other.

Other objects will he.A apparent upon in- |spcction of the following description and accompanying drawing in which- Fig. 1, represents a side view of the deviceA with most of the parts shown -in section in order to disclose the interior construction;

Fig. 2, an end view of the device of Fig. 1, portions of the armature handling and positioning means heing broken sway in ordel to more clearly show its construction;

Fig. 3. a. perspective view of tha armature unit as it appears when removed. this being the )referred form of the unit and the same as t at shown in Figs. I and 2';

Fig.'4, an end View from the left of the armature unit of Fig. 3 showing the means for adj listing the amature balancing spring Flg. 5, a side view of aI modified form oi the armature unit; 1

Fig. 6, a similar view of another modified form of the armature unit:

7, a sectional view taken on line 7-7 U of ig Fig. 8, an outer end `view' of a modified formof the armature handling and positionmvmember;

1g. 9, an end view of a modified form of the electro-magnet spool: l

Fig. 10. a lan view of tlio same:

' Fig. 1l. a ongitndnal section of another modilied form of the armature unit: and

Fig. 12, an elevation lookng'towards the inner face of a further modified form of the armature unit.

In the drawing, disclosure of any form of hase to which the device may be attached or casing in which it may he mounted is omitted for. sake of clearness. Any suitable base or casing may be used.

The assembled device which constitutes the invention, is shown in Figs. 1 and 2. The permanent magnet 1 disclosed therein is of the usual U-shaped type, but any other type suitable for the purpose may be used. Supported on the upper ieg 2 of permanent magnet 1 is the lower section 3 of the casing in which is mounted a diaphragm 4. Lower u and are threaded into. the lower section 3.

Upper casing'- section 9 is provided centrally with a tubular, exteriorly-threaded extension 11 for attachment of the device to the base of a horn or other suitable sound-amplifying means. The form of extension 11 mav be varied to conform to the construction of th .sound amplifier to which it is to be attached.

Permanent magnet 1 is provided at its not 1 in its pole pieces 12 Folin with U-shaped pole pieces I2 aud 13. ole piece' 12 is secured ri diy in place on the inner face of leg 2 o the permanent ma et bjr-means of screw 6 which is made suiligdiently long to engage a suitable threaded opening in the base of pole iecc l2. Polo Piece 13is connected rigid v to the lower eg 14 of permanent ma :et 1 by means of e. screw 15 extending t rough a suitable perforation in the le ofthe magnet and threaded into the base o the pole piece.

Mounted transversely of permanent meuf and 13 is un electro-magnet 16. The electro-nio et consists of the usual winding 17 and a anged spool 1B. rdinarily the tlattoned tube portion 19 of spool 18 and the end Hongos 20, 21 ore both formed of metal, in which cose the end ,tlang are separate piece@ which nrcsolclcrcd into place on the ends of the tube portion. In the all-metal spool tube portion 19 is Y:dotted at 22 and end Hanges 20, 2l are slotted at 23, 24 respectively. so as to prevent eddy currents from aileeting the magnetizatxon of the armature of the device.

Sometimes it is desirable to use liber end flanges on the electro-magnet spool 18, instead of the metal end lecee In this cose, as shown in Figs. 9 an 10. the tubulin' portion 19 of the spool. which io of metal, is slotted et 22. as in the all-metal spool of Figs. 1 and 2, but it is unnecessary to slot the liber end pieces.' The und nieces, 2G. 27 being of tiber. cannot he soldered to the tubular portion 19` so in order to hold them in place before the windinz 17 is put nu tubular portion 19 is provided nt its ends with extensions or ears 28 which are bont over against the outer faces' of vthe fhnge pieces after they have been slipped on the tube 10. When the winding 17 is put iu place. a very rigid and compact magnet structure is ohtained which in use is free from eddy currenin.

The armature 29 and its mounting and the means for positioning it in the device will now he described. 'llnl armature in its preferred form. as heretofore stated. is shown in Figs. 1-4 inclusive. As shown moet clearly in Fig, 1. armature 9:9, when in operative position. extends horlmntolly through the tubular portion 19 of the elcotro-luagnct 16 and projects beyond each end thereof. The armature is in the form of :i

thin. tlat metal plate and at its nnfuend' is rovidcd with a perforated extension 30..

A ink 3l. havin! a head 32 engaging the perforated extension 30 of nrmaturo29. connee-ts this end of armature 29 to diaphragm 4. In order to accommodate link 31. lcg 2 of permanent magnet 1 is provided witll an opening' 33 therethrough und lowcrncction 3 of the diaphragm casini: has a registering oneninf.'l 84 throuzh which link 31 extend. The upper end of link 3l, which is enlarged lllellllls D noaapeo und threaded. extends through a central openmgprovidcd io diaphragm 4. Mounted on theproje'ctiug threaded end of link 31 nhovc dmphragm 4 ie o threaded washer 35 und a nut 36 means of which the tension onder which t 1e diaphragm is placed may he varied to tune the instrument. Washer and nut 38 bei threaded on link 31, serre to lockeeeh ot ier in fplace and ferent accidental displacement o the tune rte. Detachahly secured on the outer ei of pole piece 1 2 by means of a 'screw 37 engazmgr a suitable threaded opening in the po e lnece is n bracket memoer 38. 'This member 1s made of non-magnetic material eo as to revent magnetization of armature 29. to wiich it is connected in a manner which will now be explained.

A. Ushapecl member 39, which is formed of line spring' wire, has its legs xed, as by soldering. in the bracket member 3R, as shown at 40. 41 (Figs. 1 and 5). The lees of member 39 extend out from bracket 38 above und parallel to arma-ture 29 and. near its base portion member 89 is bent at right angles and has the lower rtions of its legs extending through suita le aerforationszl located centrally m the arma 29. The legs of member 39 are soldered to the armature in this position, so that, as clearly shown in 1. the hase and lower Portions of the legs of member 39 profect. to

below the armature 2 9 a distance equa that of thc upper portions of the lege'alioi'e the armature. In this manner. member 39 is made to serve a two-fold purpose. It functions oe a central. transverse. pivotal support for armature 29 within the spool of ,the electro-magnet 16 and also as means ronnectimlP the armature to bracket member 38. whereby the latter may hc used. not only to remove and replace armature 29. but also to properly position it within the electrouuicrnctas will now he explained.

Tn order that. armature 29 may function properly in the operation of the receiver, it is dcerod that it he located ccntruliv hetwccu the ion and hottom walls of tubular portion 19 of the electro-marmet spool und thc pqlc pieces 12. 13. This is simply and occuratclv accomplished hv the portions of member 39 above and below armature 29. which iit snugly into tubular portion l!) of thc clcctro-maanct spool und serve to :guide tho armature 29 into proper noeition when thc ports nro beine.' assembled. For the llc-.rico to operate oflicicntly. it is also desired that armature 29 have its support or mountinfr. formed by member 30. located centrallv of tho armature and centroliv hctwccn the nds of tho electro-magnat- 16. as shown in Fin'. l. 'This is accomoliahcd h v proix'rly m'oportionina thc parts 3R and 39. so that win-n mcmhcv 3R is secured in4 place by eci-cw :ET the pivotal support of armature 2!) will lill 4 46 provided in ling 45.

be located `in the exact center of electro-4 mii net 16.

n order to transmit the vibrations set up in armature '29 byeleetro-msgnet lo, when the receiver 4is in operation,I it is necessary that the connections between the inner end of armature 29 end diaphragm t he tight.

uned up so iis to place the die hragm under tension. Menus nre provid `on bracket e pair of lugs 44, 45. Une end of springv mV 42 is lixed, es by means of soldering. lug,r 44 and its free end is disposed in e slot Intermediate its ends spring 42 is bent so as to provide e beeri portion 47 which engages with an extension 48 formed on the outer end of` ermeture 29. pring 42 henri V against the under side of ie outer end o armature 29. the armature will be balanced inst the tension of diaphragm 4 which ds to pull the inner end of the armature upward. However, as one cncl of spring 42 is freethe spring will yield so ns to permit the proper pivotal or vibrntory operation of armature 29 by electro-magnet 16. i

Means are provided Von bracket member 88'for adjusting spring 42Awith inference to armature 29. The iidjustin means consiste of e bracket 49 reinovn ly secured on the lower side of lng 4h in which is located l not screw 59. 'l'he set screw hears on spring 42 intermediate its fixed end and hearing portion 47.' It is thus possible to adjust set screw 50 so as to vary the tension of the spring' on nrmntnre 29 iis muy be desired. t icreli tuning the instrument.

From the n ive. description of the ennstruction and arrangement of the parte of the device, the facility with which the iii-mature unit may be removed for repair or other purpones .will readily he seen. This moy hc accomplished without in onywise disturbing: the e ectroineirnet 1li by first ienmving nnt 39 and washer 35 'from .the upper end of link 81 `after which the link nniy he slipped downward through the perforated extension of armature Qllniul removed through the opening I'il providedv for this {Iiirpnee in the lower leg 14 of pci'- meneot' iagnet l. Screw 37 is then removed. whereupon the entw4 armature unit may he taken ont. The unit may thon he repaired. or it may he retune'd hy means of set screw o0. after which it is replaced in the de\'ce,rbeing guided into proper posi- It will thus he seen tlnit with tion within the electro-magnet spool l8 hy means of @shaped 'member 39 and acourntely located centrally of the ends of the electro-magnetby means of the bracket member 38 when the latter is in abutting relation to the outer face of pole ieee 12. Screw 37 und the arts connecting' t e inner end of armature to dinplirn l 4 arethen replaced und ediinihnd.4 The evice is then ready for o ration. except-possibly for nilinstlnent o washer 35. nut 36 und set screw for timing.

It will be noted that in the preferred form of the armatore nuit (Figs. l-4), dependi portion 43 of bracket member 88 rtiel y conceals from view s )ring 42 und he means for adjusting it. Fig. 8 shows n modilied form of lirachet member 38 in which the depending portion 43 of member 88 is omitied and lues 44, 45 connected to the body of the bracket member bi' means of portions 5,2. 53, res irely. This nrriin ent permits e eearer view of the spring 42 and its ednsting means when the receiver is assemble In the modified forms of the armature unit shown in Figs. 5, 6 and T. the adjusting means for spring 42 are omitted for sake of clearness und this is also done in Fig.' l.

In Fig. 5. the U-rhaped member 39 for sup iai-ting and itioninp` ermntui'e 29 is rep need by n pair of spaced. vertically disposed U-sliaped members 54, the free ends of which are fixed iii bracket meinher d8` similar to the attachment of the legs'of me'mher 39 to -memher 3B. ns shown in Fin. il. Oniv the front one of the pair of U- shaped mein rs 54 is showinthe rear member being: directly behind thi` iront one. and connected to armature 29 in the eamenninncr es is the front member. Membern Fellini-o their base portions extending through and fixed in openings provided for this purpose centrally in armatore 29.*thus forming: the transverse pivotal mounting for the rinntnre. With this arrangement a more. suhst-nntinl inonntin is provided for arnintnre 29 nnd the eercrn legs of members 54 serve to increase the facility with which the armature may he positioned within the electro-magnet 16.

In t e modted armatore unit coin-truco tion of Fig. 6 the trlnsverse. pivotal mounting for nrnmtnre 29 is formed hy n rerticnlly disposed plate 5:1 having n reduced lower poi-tion Ml which extends through nml is soldered, or otherwise secured. in n trans- "rerse slot provided centrally in armatore 2l).

The portion of plate projecting alum nrmntllre 29 is connected to hreeket member :i8 by moons of wires 5T, 5B. the ends of which are jxed in pluie member 38. This modified form of the armature unit is quite similar to that shown in Fig. 3, but more iroV llll

lill

55 sind hrncket m relatively broad claims are to Fig. 11 is n modified form ofthe armature unit 1n which the position of the pivotal eprint:` member 39 with reference to armature 29 is reversed, so that the u per purl lions of the legs of member 30 arc gelen' and the base of member 39 is above the annotare. This provides a still more ellcicnt pivotal support for the armature.

n the 'form ot armature unit shown in l0 Fig. 12, the means for balancing and tuni armature 29 comprise an externally-thread tubular member or screw 59, which is mounted for adjustment in a suitable threaded opening in the lowerside et rec- IJ tnngular frame rtion 43 of bracket 38; a pin 00. mountel for free lengtlnvi morement 'in tuning screw 59 and 'provided at its upper end with a ti 6l of non-resonmnt material bearing on tie adjacent end of 1" armatore 29; an upper washer 6B which is fixed to pin 60; and a coil spring 63 mounted un pin 60 with its n per end bearing against washer 62 and its owen' end against lower washer 64 which freely' 4for n l Y 1s mounted 5 lengthwise movement on the pin.

With this arrangement. not only does the nonresonant tip 61 of the pin dampen vibration of armature 29 at this point and thus prevent chattering, but the form of the tunmg' mechanism 1s more etcient and less likely toget out of order. A. knnrled or other suitable manipulating' head G is formed on the outer end of tuning screw il!) and a lock nut 66 serves to secure the tuning screw in adjusted position. e

With any one of the above described constructions, an extremely sensitive and durable armature unit is provided. The den vice, as a whole, is of sin le 4construction ma can be easily mehr and eigenemhled. It also requires but little admet-mg to tune it. The armature unit can bei mounted on any instrument having pole peces and u an electro-magnet arranged similarly to those of the present device. e

In certain of the appended claims m npenking of the upper and lower surfaces of armature 29 the term l or @oppol." aitey faces is used and the armature is referred to' as a plate armature This is done in order to make it clear that the armature is of the llat or butterly type and therefore has op site or upper'and lower Places as dstinfuished from of re atively, thin its two opposite edges. Con uen y these terms In4 the interpreted accordmgly.

What is claimed iss- 1. In a tele hone receiver, the combination of a diep ragm; a rmlnent magnet; an electro-magnet, incl g a spool and a winding thereon; a plate amature dis sed within said spool and adapted to be operated b v the electro-magnet about n fixed plvot;

armature supporting means disposed be- 4pivotal mountlng projecting'centrally from the opposite farma of said armature and connected tween and engaging the opposite faces of the armature an the adjacent faces of said spool for pn'otally mnlulting the armature t icrcm; and a connection between the nrmn- .lure and the diaphragm. E 2. I? a ltele hone receiver, thetcolnbinznono aclap raglnn rmanen m net :In elpctrmagaet, uicludeing n spool i:51d :i winding thereon; a centrally-riveted plate armatnm di within sa d spool und adapted to be o rated by the electromagnet about a (ixe pivot; -a pivotal mounting for sind armature comprising means connectcd tu and entendi centrally from'np postte facee of the annotare into e' ment with said slmol; and a connection tween the armature and the displl n.V 3. In tele ionic apparatus, the com nahen of an e cetro-magnet, including a spool and Aa winding thereon; a centrally-pirated plate armature located within said l and adapted to be o rated by the elec net; and a pivo al mounting for the armature engaging' with the opposite faces of the armature and the adjacent faces of the spool and provided with an extension proiecting outside of the electro-magnet, said manatnrei and its ymounting; being formed as a unit for ready insertion into and re. moval from said spool bv means. of said extension withoutd saseem'bling the electromagnet.

4. A removable armahlre unit for use in a telephonereceiver eleetrmanet, which includes a spool lnd a. winding t ereon, comprising a centra lygivotd plate armature adapted to be Iocat within said spool for. operation -by the eleetro-magnet;' and a t 'tl tl t vigili forlati; nagelneu w1 i ne 1n ener o e epoo position the armature therein. Y

5. A removable armature unit for use in a telephone-receiver electrodo com-1 prising a centrally 4pivoted plate armature adapted to be located within and operated by the electro-magnet; a pivotal mounting provided centrally of the upper and lower. faces of the amature; and combined handlin'gandpositioning .means for the unit located exterior-ly of the electro-magnet and connected to said nrmature.mounting.

0. A removable' amature unit 'for use 1n a telephone-receiver, including a permanent magnet having opposed le pieces and an electro-magnet mounted 1n the pole pieces, compriaing a centrally-.pirated armature adapted to be located witlun and operated by said electro-magret; a combined handlingandpoeitioning member for the unit detachablv secured to one of said pole pieces; and a pivotal mounting povded centrally of the to the combined tioning member. le armature unit for use in o llandlingand 7. A remove a telephone receiver, includin nmgnet, an electro-ma let an aphragm, comprising a centra lyl-pivoted armature intended to be located within and operatedby said electromagnet, one end of said armature being ada ted to be connected under tension to sai( diaphragm; a pivotal mounting provided centrally of the armature for engagement with the interior of thc clcctrolma net a handlingfand-postioning member or the armutnreunt detachrmanent magnet and ably mounted on the connected to said pivotal mountin ;l and means mounted on said member to alance the armature against the tension' of the diaphragm.

S. In a sound reproducin" device of the telephone receiver type, a lfshaped permament magnet having an opening through one of the legs thereof; a casing mounted on'said leg of the permanent magnet; a diaphragm in said casing; an electro-magnet mounted between tho poles o f the permanent magnet; a piroted armature located in the electromagnet for operation thereby; and means connecting the armature with the dio phragm, said means extending through said )pemng in the leg of the permanent magnet, the other le of the permanent magnet bcing provide with an opening therethrough to permit removal of said connecting means.

9. In a tele hone receiver, the combination of a diap n'agm; a permanent magnet; an electromagnet; a centrall pivoted plate armature located within nn adapted to be operated by the electromagnet;removable,

adpermanent a i combined handling-andplgsitionin means for said armature exten g outsi e of the electro-magnet, means connecting one end of the armature to the diaphragm; and means to damp vibration of the opposite end of the armature said damping means being carried by said -lxandling-and-positoning means.

, 10. In a telephone receiver, the combination of a diaphragm; a permanent magnet; an electromagnet; a centrally pivoted 'armatnre adapted to be operated by the electromagnet; means connecting one end of the armature to the diaphragm; and spring means. for balanei the armature against the. Vtension of the 'aplu'agm, said means including a bearin against the armature. I

11. 'n a telephone receiver, the combina.- tion of a diaphragm; a permanent magnet; an clectromagnet; a centrally pivoted armature adapted to be operated by the electrolnagnet; means connectingr one end of the armature to the diaphragm; a reeiprocable member having one of its extremities formed of non-resonant material und bearing against the opposite end of the armature; a mounting for said recprocable member; and springmeans for maintaining said extremity of the reciprocable member 1n contact with the armature to balance it against tlieten sion of the diaphragm.

In testimony whereof we have signed our names to this specification. e

WILLIAM n. LA rEnnLI-z.,A WILLIAM H. La PEARLE.

rtion of nomreeonant material liti Fig. ll is a modified form of the armature unit in which the position of the pivotal spring member 3f) with referencel to armature E29 is reversed, so that the upper portions of the legs ot memler 39 are below and the base et lncmber l.) is above the armature. This provides a still more ellicient pivotal support for the armature.

In the term ot armature unit shown in Fig. 12, the means for balancing and tuning armature 29 comprise an externallytlneaded tubular member or screw 59, which is mounted for adjustment in a suitable threaded opening in the lowerside of reetangular frame portion 43 of bracket 38; a pin 60, mounted for free lengthwise movement in tuning screw 59 and provided at its upper end with a tip (il ot non-resonant material bearing on the adjacent end of armature 29: an upper washer (32 which is tixed to pin G0; and a coil spring 63 mounted on pin Gt) with its upper end bearing against washer 62 and its lower end against lower washer Gt which is mounted freely for lengthwise movement on the pin.

lVith this arrangement. not only does the non-resonant tip G1 ot the pin dampen vibration of armature 29 at this point and thus prevent chattering, but the form of the tuningI mechanism is more etlicient and less likely to `get ont of order. knurled or other suitable manipulating head 65 is formed on the outer end of timing screw 5t) and a lock nut 6G serves to secure the tuning screw in adjusted position.

lVith any one of the above described constructions, an extremely sensitive and durable armature unit is provided. The device, as a Whole. is of simple construction and can be easily assembled and disassembled. It also requires but little adjusting to tune it. The armature unit can be mounted on any instrument having pole pieces and an electro-magnet arranged similarly to those of the present device.

ln certain of the appended claims in speaking of the upper and lower surfaces ot' armature 29 the term faces or oppo- .site faces is used and the armature is referred to as a plate armature. This is done in order to make it clear that the armature is of the flat or butterfly type and therefore has opposite or upper and lower relatively broad faces as distinguished from its two opposite pairs of relatively thin edges. Consequently these terms in the claims are to be interpreted accordingly.

What is claimed is y l. In a telephone receiver, the combination of a diaphragm; a. permanent magnet; an electro-magnet, including a spool and a winding thereon; a plate armature disposed within said spool and adapted to be operated b v the electro-magnet about a fixed pivot;

armature supporting means disposed between and engaging the opposite faces `of the armature and the adjacent faces of said spool for pivotally mounting the armature therein; and a connection between the armature and the diaphragm.

2. In a telephone receiver, the combination of a diaphragm.; a permanent magnet; an electro-magnet, includingr a spool and a winding thereon; a centrally-pivoted plate armature disposed within said spool and adapted to he operated by the eleetro-mag net about a fixed pivot; a pivotal mounting for said armature comprising means connected to and extending centrally from opposite faces otl the armature into engagement with said spool; and a connection hetween the armature and the diaphragm.

3. In telephonie apparatus. the combination ot an electro-magnet, including a spool and a winding thereon; a centrally-pivoted plate armature located within said spool and adapted to be operated by the electro-magnet; and a pivotal mounting for the armature engaging with the opposite faces of the armature and the adjacent faces of the spool and provided with an extension projecting outside ot the electro-magnet. said armature and its mounting being formed as a unit for ready Vinsertion into and removal from said spool by means ot said extension without disassembling the electromagnet.

4. A removable armature unit for use in a telephone-receiver electro-magnet, which includes a spool and a Winding thereon, com prising a eentrally-pivotd plate armature adapted to be located within said spool for operation by the electro-magnet; and a pivotal mounting projecting centrally from the opposite faces ot said armature for engagement with the interior of the spool to position the armature therein.

5. A removable armature unit for use in a telephone-receiver electro-magnet comprising a centrally pivoted plate armature adapted to be located within and operated by the electroanagnet; a pivotal mounting provided centrally of the upper and lower faces of the armature; and combined handling-and-positioning means for the unit located exteriorly of the electro-magnet and connected to said armaturemounting.

6. A removable armature unit for use in a telephone receiver, including a permanent magnet having opposed pole pieces and an electro-magnet mounted in the pole pieces, comprising a eentrally-pivoted armature adapted to be located within and operated by said electro-magnet; a combined handlingand-positioning member for the unit detachably secured to ene of said pole pieces; and a pivotal mounting provided centrally of the armature and connected to the combined handling-and-positioning member.

LA removable armature unit for use in telephone receiver, including a permanent magnet. an electro-magnet and a diaphragm, omprising a centrally-pivoted armature intended to be located Within and operated by said electro-magnet, one end of said armature being adapted to be connected under tension to said diaphragm; a pivotal mounting provided centrally of the armaiure i'or engagement with the interior of the electro-magnet; a handling-and-positioningl member for the armature unit detachably mounted on the permanent magnet and connected to said pivotal mounting; and means mounted on said member to balance the armature against the tension of the diaphragm.

8. In a sound reproducing device of the telephone receiver type, a U-shaped permament magnet having an opening through one ot' the legs thereof; a casing mounted on said leg of the perumnent magnet; a diaphragm in said casing; an electro-magnet mounted between the poles of the permanent magnet; a pivot'ed armature located in the electromagnet for operation thereby; and means connecting the armature with the diaphragm, said means extending through said )pening in the leg oi the permanent magnet, the other leg of the permanent magnet be ing provided with an opening therethrough to permit removal of said connecting means.

9. ln a. telephone receiver, the combination of a diaphragm; a permanent magnet; an electromagnct; a centrally pivoted plate armature located within and adapted to be operated by the electromagnet; removable,

combined handling-andositionino means for said armature exten ing outside of the electro-magnet, means connecting one end of the armature to the diaphragm; and means to damp vibration of the opposite end of the armature, said damping means being carried by said handling-and-positioning means.

10. In a telephone receiver, the combination of a diaphragm; a permanent magnet; an electromagnet; a centrally pivoted armature adapted to be operated by the electromagnet; means connecting one end of the armature to the diaphragm; and spring means for balancing the armature against the tension of the diaphragm, said means including a portion of nonsresonant material bearing against the armature.

11. In a telephone receiver, the combination of a diaphragm; a permanent magnet; an electromagnet; a centrally pivoted armature adapted to be operated by the electromagnet; means connecting one end of the armature to the diaphragm; a reciprocable member having one of itsl extremities formed oi' nou-resonant material and bearing against the opposite end of the armature; a mounting for said reciprocable member; and spring means i'or maintaining said extremity of the reciprocable member in contact with the armature to balance it against the ten sion of the diaphragm.

In testimony whereot' we have signed our naines to this specification.

WVILLIAM E. LA PEARLE. i l/VILLIAM H. LA; PEARLE.

CERTIFIQATE 0F CORRECTION.

Patent No., l. 622. 950.

Granted March 29 i 192i, to

WILLIAM E. LA PEARLE ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, line 24, for the word "affecting" read "effecting"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office l Signed and sealed this 26th dav of April. A. D. i927.

M. J. Moore,

Seal` Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. l. 622. 950. Granted March 29. 1927, to

WILLIAM E. LA PEARLE ET AL.

It is hereby certified that error appears in the printed `Qpecification of the above numbered patent requiring correct ion as fol lows: Page 2, l ine 24, fOr the word "affect ing" read "effect ing"; and that the sa id Let ters Patent should be read wi th thi s correct ion therein that the same may conform to the record of the case in the Patent Office. i

Signed and sea led this 26th dav of Apri A. D. i927.

M. J. Moore, Seal Act ing Commissioner of Patents. 

